Effects of energy density of diets and dietary Pediococcus acidilactici supplementation on productive performance, egg quality, and intestinal function in laying hens

The objective of this study was to evaluate the effects of supplementing Pediococcus acidilactici CNCM I-4622 MA 18/5 M (PA) into diets with two energy levels on the production performance and intestinal function of Lohmann pink laying hens from 49 to 65 weeks of age. A total of 1400 hens were used in this study. A 2 × 2 + 1 experimental design with 2 metabolic energy levels (2700.00 kcal/kg, NE; 2625.00 kcal/kg, LE), two PA levels (0 mg/kg, 110 mg/kg), and one group with intermittent PA supplementation (LE-0/PA). The experiment comprised 5 treatments with 14 replications each, and each replication had 20 hens. The results showed that reducing the dietary energy level tended to decrease body weight (P = 0.056). However, supplementing PA in low-energy diets tended to increase body weight in 16 weeks (P = 0.063). The LE-0/PA group had higher laying rates and feed utilization rates compared to other groups (P > 0.05), maybe resulting in greater economic benefits. The LE group had significantly lower eggshell strength, Haugh unit, trypsin activity, lipase activity, and tibia breaking strength compared to the NE group (P < 0.05). Dietary supplementation with PA significantly increased eggshell strength (P < 0.05), tibia breaking strength, villus height/crypt depth ratio (VH/CD), lipase activity, and secretory immunoglobulin A (SIgA) content in the jejunum (P < 0.05). Additionally, PA supplementation significantly reduced the expression of interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α), toll-like receptor 4 (TLR-4), and nuclear factor kappa-B (NF-κB) mRNA (P < 0.05). In conclusion, reducing the dietary energy level of hens can reduce the body weight and feed utilization efficiency. However, dietary PA supplementation improved body weight, reduced the expression of intestinal inflammation-related factors, and enhanced intestinal health, particularly in low-energy diets. Intermittent PA supplementation may enhance performance benefits, suggesting its potential as a strategy to optimize production performance and intestinal health in hens.